CVE-2020-35971 in YzmCMS
Summary
by MITRE • 06/04/2021
A storage XSS vulnerability is found in YzmCMS v5.8, which can be used by attackers to inject JS code and attack malicious XSS on the /admin/system_manage/user_config_edit.html page.
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Analysis
by VulDB Data Team • 06/07/2021
This vulnerability represents a critical storage cross-site scripting flaw in YzmCMS version 5.8 that allows attackers to persistently inject malicious javascript code into the application's user configuration management interface. The vulnerability specifically affects the /admin/system_manage/user_config_edit.html page where user input is not properly sanitized or validated before being stored in the database and subsequently rendered back to users without adequate output encoding. The flaw enables attackers to execute arbitrary javascript code within the context of other users' browsers who visit the affected page, potentially leading to session hijacking, credential theft, or further malicious activities.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding mechanisms within the content management system's administrative interface. When administrators or other users access the user configuration edit page, any malicious javascript code injected through vulnerable input fields gets stored in the database and executed whenever the page is rendered. This persistent nature of the vulnerability classifies it as a storage XSS attack rather than a reflected XSS, making it particularly dangerous as the malicious payload remains active until manually removed from the database. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws where untrusted data is incorporated into web pages without proper validation or encoding.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with a persistent foothold within the administrative interface of the content management system. An attacker who successfully exploits this vulnerability can potentially escalate privileges, modify user permissions, access sensitive administrative functions, or use the compromised administrative session to conduct further attacks against the underlying infrastructure. The attack surface is particularly concerning because administrative interfaces typically contain sensitive configuration data and system controls that can be leveraged for more extensive compromise. This vulnerability also demonstrates the importance of proper input sanitization and output encoding practices as outlined in the OWASP Top Ten security controls, specifically addressing the need for secure input validation and output encoding to prevent XSS attacks.
Mitigation strategies should focus on immediate implementation of proper input validation and output encoding mechanisms throughout the application's data flow. Organizations should implement strict sanitization of all user inputs before storage, employ proper HTML escaping when rendering data back to users, and establish comprehensive content security policies to prevent unauthorized script execution. Additionally, regular security audits should be conducted to identify similar vulnerabilities in other parts of the application, and the system should be updated to the latest version of YzmCMS where this vulnerability has been addressed. Network monitoring and intrusion detection systems should be configured to detect suspicious activities related to administrative interface access, and access controls should be strengthened to limit the number of users with administrative privileges. The vulnerability also highlights the necessity of following ATT&CK framework principles for defensive measures, particularly focusing on preventing code injection attacks and implementing robust input validation controls to protect against such persistent threats.